Samsung SGH-I740c Service Manual page 68

10-6. Speaker Part(Melody)
Speaker does not work
U601 pin 1,7,8 and
pin 13~16 = 4.2V ?
Check the signal at
PIN R628, R629 of U601
Check pin 7, 9 at U603
Does it Work?
Check all power source
related U602 Does it
work correctly?
Check pin 35,36 at
U602 Is there signal?
Is Speaker working?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
END
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No
Resolder or Replace U601
No
IF there is no signal,
resolder or replace U601
No
Resolder or replace U603
No
Resolder U602
No
Resolder U602
No
Change the Speaker
10-20
Flow Chart of Troubleshooting